Any time I've been on an RPSI tour in their Cravens, it has been behind an 071 or 201 that is used in active duties, so there is multiple loco options available for the RPSI Cravens.
I do get the point of a steam model hauling them though, to represent the steam trips the RPSI do.
Personally, I have no interest in steam as steam was before my time, and wouldn't buy a steam loco model. I'll buy diesels till the cows come home though!